docs(src): add missing XML docs and strip tracking-ID comments

Sweep of 203 source files resolving CommentChecker findings: add
<summary>/<param>/<returns>/<inheritdoc> where missing, and remove
resolved task/issue tracking markers (Tests-NNN, Worker-NNN, Server-NNN,
Task N) from code comments. Comment/doc-only — no logic changes.
Server+Tests build clean under TreatWarningsAsErrors.

src/ZB.MOM.WW.MxGateway.Server/Sessions/SessionOpenRequest.cs

@@ -11,6 +11,7 @@ public sealed record SessionOpenRequest(
 {
     /// <summary>Creates a SessionOpenRequest from a gRPC OpenSessionRequest contract.</summary>
     /// <param name="request">Request payload.</param>
+    /// <returns>The equivalent <see cref="SessionOpenRequest"/>.</returns>
     public static SessionOpenRequest FromContract(OpenSessionRequest request)
     {
         ArgumentNullException.ThrowIfNull(request);